Ultimate Sour Lemon Bars

Crust:
1 1/2 cups all-purpose flour
1/4 cup confectioners' sugar
1 pinch salt
1/2 cup unsalted butter, cut into pieces
1/2 teaspoon vanilla extract

Topping:
5 large eggs, room temperature
2 cups sugar
1 cup fresh lemon juice, strained
3 tablespoons all-purpose flour
2 1/2 tablespoons lemon peel, grated

Heat oven to 350 degrees F. Line 9-inch square pan with foil, extending 1 inch above sides of pan. Grease uncovered 2 sides of pan.

Combine flour, powdered sugar and salt in processor. Add butter and cut in using on/off turns until mixture appears sandy. Add vanilla extract and process until dough begins to come together. Press evenly into prepared pan. Bake until golden brown, about 28 minutes.

Meanwhile, prepare topping: Whisk eggs and sugar in medium bowl to blend. Whisk in lemon juice, then flour. Strain into another bowl. Mix in grated lemon peel. Reduce oven to 325 degrees F. Pour filling over hot crust. Bake until sides are set and filling no longer moves in center when pan is shaken, about 22 minutes Cool on rack . Cover and chill at least 4 hours.

Using foil sides as aid, lift dessert from pan. Fold down foil sides. Cut into 16 squares. Cut each square diagonally in half, forming triangles. Sift top with additional confectioners' sugar.